Photoemission from graphite: Intrinsic and self-energy effects - art. no. 075105

We report a photoemission study on high-quality single-crystal graphite epi taxially grown on SiC. The results are interpreted using independent inform ation on the final states obtained by very-low-energy electron diffraction. Significant intrinsic photoemission and surface effects are identified, wh ich distort the photoemission response and narrow the observed dispersion r ange of the pi state. We assess its true dispersion range using a model pho toemission calculation. A significant dependence of the excited-state self- energy effects on the wave-function character is found. The experimental re sults are compared with a GW calculation.